Urea adducts of quaternary heterocyclic-nitrogen halides



UREA ADDUCTS F QUATERNARY HETERO- CYCLIC-NITROGEN HALIDES No Drawing. Application August 31, 1953 Serial No. 377,734'

Claims. (Cl. 260-965) This invention relates to heterocyclic-nitrogen compounds. More specifically, it relates to a novel series of chemical compositions composed essentially of urea and a quaternary heterocyclic-nitrogen compound.

One object of our invention is to convert quaternary ammonium compounds of the heterocyclic-nitrogen type into a form more readily and conveniently stored, handled, measured,'and applied. Another object is to convert urea into a more effectively utilizable form. Another object is to prepare a chemical combination of'urea and a quaternary ammonium compound of the heterocyclicnitrogen class having advantageous properties as a nutrient and an antibiotic when employed in plant sprays, A further object is to separate quaternary heterocyclic nitrogen compounds into classes according to structural configuration. Other objects of our invention will be apparent from the description thereof and the appended claims. v

Quaternary heterocyclic-nitrogencompounds, such as N-laurylpyridinium chloride, N-cetyl-N-methylpiperidinium bromide, and the like, are evil-smelling, pasty, or semicrystalline masses as ordinarily prepared. In consequence, they are diflicult to measure, handle,'and store, and are objectionable in many applications for'which they would otherwise be adapted. We have now discovered that quaternary heterocyclic-nitrogen compounds of a certain structure can be converted into odorless, free-flowing powders by reaction wtih urea according to methods wellknown in the art to form crystalline adducts thereof. The improved physical characteristics of the said adducts permit commercial utilization of the desirable fungicidal and germicidal properties of the nitrogen compounds in applications which have heretofore not been feasible.

The urea-reactive class of nitrogen compoundsemployed in producing the adducts of our invention are quaternary-ammonium compounds wherein the nitrogen atom exists as part of a heterocyclic ring structure. Thus, the said compounds may be considered to be derivatives of heterocyclic amines, wherein the ring nitrogen-may be unsaturated (i. e., joined in the ring with a single bond and a double bond) as in pyridine, alpha-picoline, betapicoline, quinoline, and the like, or saturated (i. e.,

joined in the ring with two single bonds) as in pyrrole, pyrroline, pyrrolidine, piperidine, and the like; In the case of an unsaturated ring-nitrogen compound, the quaternary ammo'nium compound is formed in effectby attaching to the nitrogen atom a straight-chain organic radical containing at least five methylene groups, thereby satisfying all of the non-ionic valence bonds thereof. In the case of a saturated ring-nitrogen compound, a methyl group is additionally joined to the nitrogen atom in order to satisfy the fourth non-ionic valence. Thus, our urea nite rates Paten a nitrogen atom is joined to a Patented Apr. 8, 1958 methyl group. The straight-- chain attachment for'the nitrogen atom should contain at least 5 methylene groups, and may suitably be n-alkyl; n-alkenyl, n-alkynyl, n-alkadienyl, n-oxaalkyl I stroyed by the substitution on the straight-chain radical of a hydroxyl or fluorine in any position, or by substitution thereon of other halogen, amine, or mercapto group in the omega position. The most useful groupof our new compositions which we have so far prepared are obtained from heterocyclic quaternary-ammonium salts containing a C -C n-alkyl group. These compounds have excellent germicidal, fungicidal, and surface-active properties, which are retained and improved when the compounds are reacted with urea.

Quaternary compounds for use inour invention may conveniently beprepared according to the method of Shelton et.al., described in the Journal of the American Chemical Society, 68 (1946), 757. In this method, an approximately equimolarmixture of heterocyclic-nitrogen compound and an alkyl halide, for example, are heated at to 130 C. for several hours, chlorides requiring a longer time than bromides. The reaction product is crystallized twice from acetone and dried in vacuumat 25 C., yielding a dry, almost white solid.

The. preparation of our new compositions of matter is carried out by reacting urea with a heterocyclic quaternary-ammonium compound of. our defined class according to methods described in the prior art. The quaternary compound is preferably dissolved in any organic liquid, such as methanol, ethanol, n-butyl alcohol, ethylene glycol, or the like, which serves simultaneously to dissolve the quaternary compound and reduce the viscosity thereof, and to activate the urea for adduct formation.

The resulting solution is contacted with urea. For complete reaction of the quaternary compound with urea, at least one mole of urea should be used for each methylene group in the straight-chain organic radical attached to the nitrogen atom; When substantially pure'adducts are is a slurry of the desired urea adduct in the diluent liquid.

The slurry is subjected to filtration, settling and decantation, centrifugation, or the like to separate the adduct,

and the adduct is washed with a quantity of cold diluent liquid to remove entrained mother liquor therefrom. The

adducts are formed from quaternary-ammonium comwashed solid is then dried The dry solid is the new composition of our invention, suitable Without further treatment for the many uses to which it is adapted.

It will be apparent that numerous variations of the above procedure maybe employed for making our new compositions. The following variations are illustrative:

(1) An excess of a quaternary-ammonium compound of the defined class is stirred at room temperature with a saturated solution of urea in a urea. solvent, such as a lower aliphatic (C to C alcohol. The adduct that precipitates is filtered off, washed with a low-boiling solvent such as acetone or ether, and dried. The un-' reacted quaternary'comp'ound'in the washiliquor'is re'- cycled.-. I

(2) Theoretical proportions of urea and the quaternary compound are dissolved .in a lower aliphatic alcohol, and

the solution is spray-dried... v

(3) A1concen,trated solution (for-example, 50 to 75 percentby weight) of the quaternary compound in a, lower aliphatic alcohol is mixed with the theoretical proportion of dried, powdered urea, the mixture, 18 stirred until it becomes homogeneous, and the resulting slurry 1s dried.

(4) An unsaturated alcoholic solution of urea and a quaternary-ammonium compound of the defined class in approximately theoretical proportions is d1luted with an organic liquid, such as ethyl ether, which functions as an alcohol solvent and a urea-adduct antisolvent. The precipitated adduct is filtered off and dried.

A mixture of quaternary-ammonium compounds is treated with'urea according to any of the foregoing methods. The resulting urea adduct contains only our defined class of urea-reactive quaternary-ammonium compounds. These procedures therefore afford a method for separating the said classes of quaternary-ammonium compounds from other types.

Our invention will be more fully following specific. examples:

Example 1 A solution of three grams of commercial-gradeN- laurylpyridinium chloride in five milliliters of methanol was rapidly'rnixed at room temperature with a saturated solution of grams of urea in methanol. A precipitate began to form within a few minutes, and after 0.5 hour it was separated by filtration and washed on the filter funnel with ethyl ether. On being dried, the product was found to be a fine, white, odorless powder whichassayed 3.59 percent by weightofchlorine, corresponding to 28 percent by weight of N-laurylpyridinium chloride in the complex or about 12'moles of urea per mole of quaternary compound. The odoriferous impurities from the original commercial-grade material were found in the filtrate.

understood from the Example 2 A mixture of threegrams of N-n-octadecylpyridinium bromide, 10 grams of urea, and milliliters of methanol was stirred and warmed to obtain complete solution, then. cooled to room temperature for about an hour. The resulting slurry was filtered, and the solid was washed with a little ether and dried. The dry product weighed 8.3 grams and contained 5.4 percent by weight of bromine, compared with a theoretical bromine content of 19.4 percent by weight in the original quaternary compound.

' Example 3 A mixture of 1.5 grams of N-cetyl-alpha-picolinium end of one hour.

, 4 Example 6 A solution containing 10 grams of N-cetyl-N-methylv piperidinium bromide in 50 milliliters of methanol was commingled at room temperature with a solution of 30 grams of urea in 150 milliliters of methanol,-and the mixture was allowed to stand. Crystals began forming at once, and the reaction appeared to be complete at, the The crystals were then filtered off, washed with ethyl ether, and dried in a vacuum. The dry product weighed 10 grams and contained 6.08 percent by weight of bromine, compared with 18.5 percent by weight of bromine theoretically'present in the original quaternary compound. In view of the reaction procedure employed, it was obvious that the crystals could not be either urea or quaternary compound alone, and

the halogen analysis indicated that the crystalline adduct bromide, 5.0 grams of urea, and 25 ml. of methanol was reacted as.described in Example 2. The ;dry product weighed 3.8 grams and contained 6.46 percent by weight of bromine, compared with 20 percent by weight of bromine inthe original quaternary compound.

Example 4 A mixture of 1.0 gram of N-cetylquinolinium bromide,

3.3 grams of urea, and 17 milliliters. of methanol was reacted as described in Example 2. The dry product weighed 2.1 grams and contained 4.82 percent by weight "ducing actions are highly desirable.

contained approximately 3 parts by weight of urea per part of quaternary compound.

Our new products have outstanding advantages in many uses. They are-non-hygroscopic, free-flowing talc-like powders which are easily packaged, measured, blended, and dissolved. They retain their free-flowing, powdery character in storage and under conditions of high humidity. They are readily produced in constant and unvarying composition, and can therefore be standardized on apotency basis. They may be readily combined with other ingredients in dusting powders, in aqueous solutions, or in emulsions. The urea, being non-ionic, does not in terfere with the characteristic properties of the heterocyclic quaternary ammonium compound employed, such as surface activity, or fungicidal or germicidal activity.

Surface-active quaternary compounds reduce the surface tension of'aqueous solutions of the adduct, and facilitate spreading and penetration of the urea in certain applications. All of these advantages represent striking improvements over the heterocyclic quaternary ammonium compounds of the prior-art.

Our new compositions are useful in a wide range of applications. They may be used as a combination plant food and fungicide for fruit trees, and plants in general. For this purpose, they can be conveniently used as dust, owing to the fact that they are free-flowing, non-hygro scopicpowders; and they can conveniently be combined with insecticidal agents and inert materials which are commonly applied separately. Since garden crops or ornamental plants are commonly dusted in the morning when the plants are wet with dew, the use of our new compositions or materials comprised thereof at such time's isdefinitelyadvantageous, permitting rapid decomposition of the urea adduct and immediate feeding and fungicidal activity by the urea and the quaternary compound.- Alternatively, our new compositions can be used advantageously as a component of sprays for plants and trees. .Inthis connection, it is highly advantageous to employ adducts of quaternary' compounds having surfaceactive characteristics. When such an adduct is added to water,,it. decomposes, yielding a solution which has a lowerlsurface tension than a comparable ureasolution,

and for this reason it is more capable and efiicient in feedingnitrogen to plants. It a higher ratio of urea is desired, an additional quantity of urea can be blendedwith the adduct, owing to the powdery form of the latter. Our new compositions are also useful in pharmaceutical preparations, for example in mouthwashes, tooth pastes, and the like, where the fluoride salts of the quaternary ammonium compound may advantageously be employed. They are especially useful in tooth powders, where their non-hygroscopic nature meets an essential qualification, and where their combined germicidal and ammonia-pro- Many other uses will be apparent to those skilled in the art;

ofbromine, compared with 18.4 percent'by weight of bromine theoretically: present in the original quaternary omp un While we have described our invention with reference to certain specific embodiments thereof, it should be understood that such embodiments are illustrative only and not by way of limitation. Various modifications of our invention and alternative charging stocks, operating procedures, and conditions will be apperent from the foregoing description to thoseskilledin the art.

In accordance with the foregoing description, we claim as our invention:

1. An adduct of urea and a heterocyclic quaternaryammonium halide wherein the nitrogen atom exists as part of a heterocyclic ring, and wherein the nitrogen atom is further joined to an unsubstituted straight-chain organic radical containing at least five methylene groups, and wherein any otherwise unattached non-ionic valence bond of the nitrogen atom is joined to a methyl group.

2. An adduct of urea and a heterocyclic quaternaryammonium halide wherein the nitrogen atom exists as part of a heterocyclic ring, and wherein the nitrogen atom is further joined to a C -C straight-chain aliphatic radical, and wherein any otherwise unattached non-ionic valence bond of the nitrogen atom is joined to a methyl group.

3. An adduct of urea and a quaternary-ammonium halide wherein the nitrogen atom exists as part of a heterocyclic ring, and wherein the nitrogen atom is further joined to an n-alkyl radical containing at least six carbon atoms, and wherein any otherwise unattached non-ionic valence bond of the nitrogen atom is joined to a methyl group.

4. An adduct of urea and a quaternary-ammonium chloride wherein the nitrogen atom exists as part of a ther joined to a C -C n-alkyl radical, and wherein any otherwise unattached non-ionic valence bond of the nitrogen atom is joined to a methyl group.

5. An adduct of urea and a quaternary-ammonium bromide wherein the nitrogen atom exists as a part of a heterocyclic ring, and wherein the nitrogen atom is further joined to a C -C n-alkyl radical, and wherein References Cited in the file of this patent UNITED STATES PATENTS 2,295,606 Riethof Sept. 15, 1942 2,346,632 Wolfert et a1. Apr. 11, 1944 2,541,248 Hibbs Feb. 13, 1951 2,642,423 Gorin June 16, 1953 2,676,955 Weitkamp et a1. Apr. 27, 1954 OTHER REFERENCES Lawrence: Surface-Active Quaternary Ammonium Germicides (pages 4 through 8). Academic Press, Inc.,

heterocyclic ring, and wherein the nitrogen atom is fur- New York (1950). 

1. AN ADDUCT OF UREA AND A HETEROCYCLIC QUATERNARYAMMONIUM HALIDE WHEREIN THE NITROGEN ATOM EXISTS AS PART OF A HETEROCYCLIC RING, AND WHEREIN THE NITROGEN ATOM IS FUTHER JOINED TO AN UNSUBSTITUTED STRIGHT-CHAIN ORGANIC RADICAL CONTAINING AT LEAST FIVE METHYLENE GROUPS, AND WHEREIN ANY OTHERWISE UNATTACHED NON-IONIC VALENCE BOUND OF THE NITROGEN ATOM IS JOINED TO A METHYL GROUP. 